<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>label</title>
</head>
<body>
<!--    small是副标题-->
    <h1>h1,Bootstrap heading<small>secondary</small></h1>
<!--文本对其类 包括 center right-->
    <p class="text-left"> left aligned text </p>
<!--改变大小写 uppercase capitalize -->
<p class="text-lowercase">Lowercased text</p>
<!--缩略语句-->
<p> An abbreviation of the word attribute is <abbr title="attribute">attr</abbr></p>
</body>
</html>